A sensitive new microculture method for diagnosis of cutaneous leishmaniasis

A sensitive microcapillary culture method (MCM) was developed for rapid diagnosis of cutaneous leishmaniasis (CL). The MCM is superior to the traditional culture method (TCM) as determined by the smaller inoculum size, the higher sensitivity for detection of promastigotes, and the more rapid time for emergence of promastigotes. With lesion amastigote loads from grade III to 0, the positive rates and the periods for promastigote emergence were 3-4-fold higher and faster with the MCM than with the TCM, e.g., 83-97% positive in 4-7 days versus 20-40% positive in 15-30 days (P = 0.0001). The higher Pco(2) and lower Po(2) and pH presumably encourage a rapid amastigote-to-promastigote differentiation and/or the survival or growth of the latter. This MCM has the advantage of simplicity, and may be suitable for diagnostic use and for parasite retrieval in many other endemic sites where parasites are known to be difficult to grow.